Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Results

Summary quarterly results for the two years ended December 31, 2016 are as follows (in thousands, other than share and per share data):

	Three months ended												Full year
2016	March 31			June 30			September 30			December 31
Revenue	$	4,287		$	3,535		$	7,086		$	4,722		$	19,630
Gross loss	$	(5,419	)	$	(4,051	)	$	(11,646	)	$	(4,891	)	$	(26,008	)
Loss from operations	$	(8,156	)	$	(8,150	)	$	(24,769	)	$	(21,642	)	$	(62,717	)
Loss before income taxes	$	(7,484	)	$	(8,383	)	$	(25,017	)	$	(22,218	)	$	(63,102	)
Net loss	$	(7,333	)	$	(8,209	)	$	(24,801	)	$	(22,536	)	$	(62,879	)
Basic and diluted loss per common share	$	(0.28	)	$	(0.31	)	$	(0.94	)	$	(0.85	)	$	(2.39	)
Weighted average common shares outstanding used in computing net loss per common share, basic and diluted:		26,226,614			26,296,398			26,374,516			26,527,909			26,356,359
	Three months ended												Full year
2015	March 31			June 30			September 30			December 31
Revenue	$	8,910		$	7,106		$	5,346		$	2,456		$	23,818
Gross loss	$	(5,109	)	$	(5,155	)	$	(3,891	)	$	(8,988	)	$	(23,143	)
Loss from operations	$	(7,948	)	$	(8,322	)	$	(47,370	)	$	(12,309	)	$	(75,949	)
Loss before income taxes	$	(8,312	)	$	(8,529	)	$	(48,859	)	$	(12,156	)	$	(77,856	)
Net loss	$	(8,348	)	$	(8,580	)	$	(48,196	)	$	(12,706	)	$	(77,830	)
Basic and diluted loss per common share	$	(0.32	)	$	(0.33	)	$	(1.84	)	$	(0.49	)	$	(2.98	)
Weighted average common shares outstanding used in computing net loss per common share, basic and diluted:		26,129,276			26,142,261			26,160,308			26,192,838			26,156,170